It D hope that helps Have a good day
Reduce the risk of waterborne disease
Answer:
The correct answer is A. active transport
Explanation:
There are two types of transport which helps in the transport of molecules across the cell membrane. These are active transport and passive transport. In passive transport, the molecules move across the membrane without any energy expenditure and down their concentration gradient.
In active transport, molecules move against their concentration gradient with the help of ATP so in active transport, molecules can be present in high concentration outside or inside the cell.
Sodium is an ion that moves by active transport in and out of the cell with the help of sodium-potassium pump so it's so the correct answer is A.